Kinetic analysis for the effect of intramolecular hydrogen bonding on photophysical properties of N-hydroxyalkyl-1, 8-naphthalimides

Article abstract of DOI:10.1246/bcsj.20090330

N-(2-hydroxyethyl)-, N-(2-methoxyethyl)-, N-(3-hydroxypropyl)-, and N-(3-methoxypropyl)-1, 8- naphthalimide (1, 2a, 2b, 3a, and 3b, respectively) were prepared and their photophysical properties examined. The UV and IR spectra of 2a and 3a indichloromethane showed the presence ofintramolecular hydrogen bonding between the carbonyl group and the hydroxy group. In addition, the fluorescence intensities of 2a and 3a indichloromethane were found to be about two times larger than those of 1, 2b, and 3b. Furthermore, the fluorescence lifetimes of 2a and 3a, determined by picosecond single photon counting, were about two times longer than those of 1, 2b, and 3b. The rate constants of the intersystem crossing (k_isca nd 3a, calculated based on the quantum yields of the intersystem crossing (P_isc) determined by the time-resolved thermallensing technique, were about one half of those obtained for 1, 2b, and 3b, while the rate constants of fluorescence emission (k _f) and internal conversion (k_ic) were minimally affected by the presence of intramolecular hydrogen bonding. Enhancement of the fluorescence quantum yield and the lifetime of 2a and 3a was thus explained by a decrease in the efficiency of the intersystem crossing from 1(ππ*)to 3(nπ*), that results from an increase in the energy of the 3(nπ*) level due to the presence of intramolecular hydrogen bonding.

Full text of DOI:10.1246/bcsj.20090330

©
2010 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 83, No. 9, 1067–1073 (2010) 1067
Kinetic Analysis for the Effect of Intramolecular Hydrogen Bonding
on Photophysical Properties of N-Hydroxyalkyl-1,8-naphthalimides
1
1
1
Kazuhiko Matsubayashi, Chisato Kajimura, Hideo Shiratori,
1
2
2
Yasuo Kubo,* Toshitada Yoshihara, and Seiji Tobita
1Department of Materials Science, Faculty of Science and Engineering, Shimane University, Matsue 690-8504
2Department of Chemistry, Gunma University, Kiryu 376-8515
Received December 11, 2009; E-mail: kubo@riko.shimane-u.ac.jp
N-Methyl-, N-(2-hydroxyethyl)-, N-(2-methoxyethyl)-, N-(3-hydroxypropyl)-, and N-(3-methoxypropyl)-1,8-
naphthalimide (1, 2a, 2b, 3a, and 3b, respectively) were prepared and their photophysical properties examined. The
UVand IR spectra of 2a and 3a in dichloromethane showed the presence of intramolecular hydrogen bonding between the
carbonyl group and the hydroxy group. In addition, the fluorescence intensities of 2a and 3a in dichloromethane were
found to be about two times larger than those of 1, 2b, and 3b. Furthermore, the fluorescence lifetimes of 2a and 3a,
determined by picosecond single photon counting, were about two times longer than those of 1, 2b, and 3b. The rate
constants of the intersystem crossing (kisc) for 2a and 3a, calculated based on the quantum yields of the intersystem
crossing (Φisc) determined by the time-resolved thermal lensing technique, were about one half of those obtained for 1,
2b, and 3b, while the rate constants of fluorescence emission (kf) and internal conversion (kic) were minimally affected by
the presence of intramolecular hydrogen bonding. Enhancement of the fluorescence quantum yield and the lifetime of 2a
1
3
and 3a was thus explained by a decrease in the efficiency of the intersystem crossing from (³³*) to (n³*), that results
3
from an increase in the energy of the (n³*) level due to the presence of intramolecular hydrogen bonding.
Hydrogen bonding in the ground state is known to play an
the photoreactions of naphthalimides have been investigated in
the past decade by Kubo and co-workers.
We have recently shown that the fluorescence intensity
and photoreactivity of N-methyl-1,8-naphthalimide (1) are
remarkably increased by intermolecular hydrogen bonding
with alcohols, possibly through a decrease in the efficiency
important role in chemistry and biology.1 On the other hand,
intermolecular hydrogen bonds formed in the excited state have
often been observed to be stronger than those in the ground
,2
20
3
state due to specific charge localization in the exited state.
Strong hydrogen bonding in the excited state has been reported
to induce efficient radiationless deactivation, electron trans-
1
3
of intersystem crossing from (³³*) to (n³*), because the
4
,5
6
3
fer, and energy transfer. Formation of intermolecular hydro-
gen bonds has also been found to have a significant influence
on the photophysical behavior of various compounds, espe-
cially heterocyclic aromatic7 and carbonyl compounds.
Formation of hydrogen bonds has been shown to have different
effects on the energies of various excited states; in an extreme
case, hydrogen bonding caused the reversal of close-lying n³*
energy of the (n³*) level increases as a result of the hydrogen
2
1
bonding. In this paper, we report the photophysical properties
of N-methyl-, N-(2-hydroxyethyl)-, N-(2-methoxyethyl)-, N-(3-
hydroxypropyl)-, and N-(3-methoxypropyl)-1,8-naphthalimide
(1, 2a, 2b, 3a, and 3b, respectively; Scheme 1) to clarify the
mechanistic details of the effect of hydrogen bonding on the
photophysical properties of naphthalimide derivatives.
8,9
1
0
and ³³* states. In addition, the difference in strength of
hydrogen bonding between the ground and the excited states
R
8
,9,11
has been reported to lead to efficient energy dissipation.
O
N
O
Derivatives of 1,8-naphthalimide have been extensively
studied in recent decades owing to their interesting photo-
1
2
physical properties and the wide range of applications they
find in chemical and biochemical areas. Many naphthalimide
chromophores, characterized by both intense absorption and
high fluorescence quantum yields, have been prepared in the
last century and used as dyes13 or brighteners.14 Several 1,8-
1 ; R = Me
a ; R = (CH ) OH
2
naphthalimide-containing compounds have been described as
photo-inducible DNA-cleaving agents15 and tumoricidals,
some of which have entered clinical trials owing to their
strong anticancer activity.17 The 1,8-naphthalimide moiety has
also been used to design fluorescent molecular probes sensitive
2 2
16
2b ; R = (CH ) OMe
2
2
3a ; R = (CH ) OH
2
3
3
b ; R = (CH ) OMe
2
3
1
8
19
to variations in pH or metal ion concentration. Meanwhile,
Scheme 1.
Published on the web August 21, 2010; doi:10.1246/bcsj.20090330

1
068 Bull. Chem. Soc. Jpn. Vol. 83, No. 9 (2010)
.0
Photophysical Properties of Naphthalimides
1
C=O str.
2a, 3a
Abs
1
, 2b, 3b
1
2
2
3
a
b
a
0
3
00
350
wavelength / nm
Figure 1. UV spectra of naphthalimides 1­3 (0.075 mM) in
dichloromethane.
0
.6
3
b
Abs
1
700
11600
wavenumber / cm-
Figure 3. IR spectra of the ¯C=O region of naphthalimides
­3 (20 mM) in dichloromethane.
1
0
3
00
350
wavelength / nm
3a, DFT calculations (geometry optimizations) for these
2
2
compounds at the RB3LYP /6-31+G(d) level were examined
using the Gaussian 03 package. The calculations indicate that
the hydrogen bonding geometries (HB form) are more stable
than the corresponding non-hydrogen bonding geometries
Figure 2. UV spectra of naphthalimides 1­3 (0.060 mM) in
methanol.
23
(
non-HB form) for 2a and 3a (Figures 4 and 5, respectively).
Results and Discussion
These results further support the presence of intramolecuar
hydrogen bonding in 2a and 3a.
UV and IR Spectra.
To prove the existence of intra-
molecular hydrogen bonding in the ground state, UVabsorption
spectra of 2a and 3a in dichloromethane were measured
together with those of 1, 2b, and 3b (Figure 1). The absorption
spectra of 2a and 3a were found to be clearly red-shifted
compared with those of 1, 2b, and 3b, which were indistin-
guishable. These results indicate the presence of intramoleculer
hydrogen bonding in 2a and 3a.
Fluorescence Spectra.
To confirm that intramolecular
1
1
hydrogen bonding has an effect on 2a* and 3a*, fluorescence
spectra of 2a and 3a in dichloromethane were measured
together with those of 1, 2b, and 3b. Figure 6 shows that the
fluorescence intensities of 2a and 3a are about two times larger
than those of 1, 2b, and 3b.
In methanol, however, the fluorescence spectra of com-
pounds 1­3 showed no clear systematic variations; the relative
fluorescence intensities of 1, 2a, 2b, 3a, and 3b were 1.00,
0.80, 0.90, 1.08, and 0.87, respectively.
In methanol, however, the absorption spectra of compounds
1
­3 were indistinguishable. It is possible that the intramolec-
ular hydrogen bonding in 2a and 3a is disrupted by the polar
protic solvent (Figure 2).
Fluorescence Quantum Yields and Lifetimes.
The
IR spectra of 2a and 3a in dichloromethane were measured
together with those of 1, 2b, and 3b (Figure 3). Figure 3 shows
the slight red-shift and broadening of the intense absorption
bands attributed to the ¯C=O of 2a and 3a. These results
further indicate the formation of hydrogen bonds between the
carbonyl group and the intramolecular hydroxy group in 2a
and 3a.
fluorescence decay profiles for compounds 1­3 were measured
by the picosecond single photon counting method. Typical
fluorescence decay profiles for 1 and 2a in dichloromethane are
1
1
shown in Figure 7 and the lifetimes (¸ ) of 1* and 2a* were
f
determined to be 180 and 371 ps, respectively. The fluores-
cence quantum yield (Φ ) values for 1­3 in dichloromethane
f
were determined as relative values to those obtained for 1
1
2
DFT Calculations.
To elucidate the nature of the
in acetonitrile (Φ = 0.027). The values for ¸ and Φ of
f f f
intramolecular hydrogen bonds in the ground states of 2a and
compounds 1­3 in dichloromethane at ambient temperature

K. Matsubayashi et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 9 (2010) 1069
1
.224
1
.413
1.225
1.410
0
.976
1
.396
1.398
0.975
1
.925
1
.233
1.977
1.233
O
N
O
O
N
O
HO
2
a
HO
HB form
3a
HB form
0.969
0.969
1
.225
1
.406
1.226
1.406
1
.406
1.406
1
.225
1.226
O
N
O
OH
O
N
O
OH
2
a
non-HB form
3a
Figure 4. Optimized hydrogen bonding geometry (HB
non-HB form
¹1
form, total energy = ¹262.91533 kcal mol ) and non-
hydrogen bonding geometry (non-HB form, total
Figure 5. Optimized hydrogen bonding geometry (HB
form, total energy = ¹287.32382 kcal mol ) and non-
hydrogen bonding geometry (non-HB form, total
energy = ¹286.80799 kcal mol ) for naphthalimides 3a
calculated using RB3LYP/6-31+G(d) (lengths in ¡).
¹1
¹1
energy = ¹262.72322 kcal mol ) for naphthalimide 2a
calculated using RB3LYP/6-31+G(d) (lengths in ¡).
¹1
are summarized in Table 1. It can be seen that both the ¸ and
f
Φ values for 2a and 3a, in which the intramolecular hydrogen
bond is formed, are about two times greater than those obtained
for 1, 2b, and 3b.
f
¹
1
¹1
the excitation photon energy (80.5 kcal mol , 28170 cm ) and
1
the average energy dissipated by fluorescence from 1­3*,
Quantum Yields and Rate Constants. To establish the
cause of the increase in ¸ and Φ values for 2a and 3a, the
respectively. The ET value of 1 was determined to be
¹
1
52.9 kcal mol from the 0­0 band of the phosphorescence
spectrum of 1 in EPA at 77 K, and the hEsi value of 1 was
f
f
quantum yields for intersystem crossing (Φ ) in compounds
isc
¹
1
1
­3 were determined by using the time-resolved thermal
determined to be 75.64 kcal mol from the wavelength of the
maximum intensity of the fluorescence of 1 in dichloro-
methane. The slow rise component for 1, which corresponds to
24
lensing (TRTL) method. Typical TRTL signals for 1 and 2a in
dichloromethane are shown in Figure 8.
3
The ratio Uslow/Utotal of the intensity of the slow rise
component (Uslow) and that of the total TRTL signal (Utotal) is
given by:
the slow thermal release from 1*, was slightly larger than that
for 2a. The Φisc values of 1 and 2a were estimated by eq 1, and
the Φic value was calculated by:
Uslow
Utotal
ꢀiscET
ꢀ
ic ¼ 1 ꢀ ꢀf ꢀ ꢀisc
ð2Þ
¼
ð1Þ
Eex ꢀ ꢀfhEsi
The values of the quantum yields Φ , Φ , and Φ for
compounds 1­3 are also included in Table 1.
f
isc
ic
3
where E , E , and hEsi are the 0­0 transition energy of 1­3*,
T
ex

1
070 Bull. Chem. Soc. Jpn. Vol. 83, No. 9 (2010)
Photophysical Properties of Naphthalimides
1
0000
2
a
3
a
1
000
2a
1
00
Lamp
1
2
b
1
0
1
3
b
1
−0.5
0.5
1.5
2.5
Time / ns
4
00
500
Figure 7. Fluorescence decay curves of naphthalimides 1
and 2a (0.022 mM) in dichloromethane.
wavelength / nm
Figure 6. Fluorescence spectra of naphthalimides 1­3
0.075 mM) in dichloromethane.
(
Table 1. Photophysical Parameters of Naphthalimides 1­3 in Dichloromethane
¸
f
kf
/10 s
kisc
/10 s
kic
/10 s
kq¸
/M
kq
M
Imide
Φf
Φisca)
Φic
8
¹1
9
¹1
8
¹1
¹1
/1010
¹1
s¹1
/ps
1
180
371
172
358
141
0.030
0.060
0.029
0.057
0.023
0.92
0.85
0.91
0.86
0.94
0.05
0.09
0.06
0.08
0.04
1.7
1.6
1.7
1.6
1.6
5.1
2.3
5.3
2.4
6.7
2.8
2.4
3.5
2.2
2.8
2.89
5.37
2.54
5.46
2.18
1.62
1.45
1.48
1.52
1.55
2a
2b
3a
3b
a) The Φisc values determined using the TRTL method.
The rate constants for fluorescence emission (k ), intersystem
f
crossing (k ), and internal conversion (k ) for compounds 1­3
isc
ic
were calculated by substituting the values determined for Φf,
Φ , Φ , and ¸ into eqs 3, 4, and 5, respectively:
Uslow
isc
ic
f
kf ¼ ꢀf¸fꢀ
1
ð3Þ
ð4Þ
ð5Þ
ꢀ
1
Utotal
kisc ¼ ꢀisc¸f
kic ¼ ꢀic¸fꢀ
1
(a) 1
The values of k , k , and k for compounds 1­3 in
f
isc
ic
-50
150
350
dichloromethane at ambient temperature are also presented in
Table 1. It can be seen in the table that the values for k
isc
8 ¹1
9
¹1
(
µ10 s ) are significantly larger than those for k (µ10 s )
f
8
¹1
and k (µ10 s ) for all of the compounds in dichloromethane,
ic
indicating that the intersystem crossing is the most dominant
1
Uslow
relaxation process (Φisc > 0.85) from 1­3*. Furthermore, the
kisc values for 2a and 3a decrease to about one half of the
values obtained for the other naphthalimides. In the cases of kf
and k , minimal differences were observed. Thus, the intra-
molecular hydrogen bonding in 2a and 3a may only affect the
ic
Utotal
rate of intersystem crossing (kisc).
(b) 2a
Fluorescence Quenching. The fluorescence of compounds
1
­3 was quenched by the presence of styrene in dichloro-
-
50
150
350
methane without any change in the shape or wavelength of the
maximum emission. Typical examples for 1 and 2a are shown
in Figure 9. Stern­Volmer plots for the fluorescence quenching
gave straight lines against the concentration of styrene. The
Time / µs
Figure 8. Time-resolved thermal lensing signals of naph-
thalimides 1 and 2a (0.022 mM) in dichloromethane.

K. Matsubayashi et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 9 (2010) 1071
Stern­Volmer slopes (k ¸ ) and rate constants for fluorescence
times larger than those obtained for the other naphthalimides,
q
f
quenching (k ) for compounds 1­3 are summarized in Table 1
the rate constants of the fluorescence quenching (k ) for 2a and
q
q
as well. While the values of k ¸ for 2a and 3a are about two
3a are comparable to the diffusion-controlled rate constant in
dichloromethane and almost identical to those of 1, 2b, and 3b,
indicating that the intramolecular hydrogen bonding has very
little effect on the rate of fluorescence quenching by styrene.
Mechanism. As shown above, intersystem crossing in 1
q
f
Me
N
(a)
O
O
+
Ph
1
accounts for more than 85% of the relaxation process of 1*.
The results may indicate that the lowest singlet excited state
0
mM
1
1
3
(
³³*) and the upper triplet excited state (n³*) levels of 1 are
5
0 mM
1
1
2
00 mM
50 mM
00 mM
close together in energy.
On the other hand, fluorescence quantum yields (Φ ) for
f
2
a and 3a increased due to the presence of intramolecular
hydrogen bonding. Hydrogen bond formation is known to
increase the energy of the n³* state compared with that of the
2
5
1
3
³
³* state. The (³³*) and (n³*) levels in 2a and 3a are
400
500
close together in energy, but intramolecular hydrogen bonding
in these two naphthalimides may increase the energy of the
wavelength / nm
3
1
(
n³*) compared with that of the (³³*), thus decreasing the
OH
(b)
1
3
rate of intersystem crossing from the (³³*) to the (n³*) level
and resulting in an increase in the fluorescence quantum yield
O
N
O
(
Φ ) (Scheme 2).
f
+
Ph
Conclusion
Prezhdo et al. have reported that the ability of N-hydroxy-
0
mM
2
a
2
5
7
5 mM
0 mM
5 mM
alkyl-1,8-naphthalimides to form intramolecular hydrogen
bonds depends on the number of OH groups, and that the
introduction of a single OH group does not increase the
1
00 mM
2
6
fluorescence quantum yield. Thus, only N-(1,1-dihydroxy-
methyl-2-hydroxy)ethyl-1,8-naphthalimide (4) (Chart 1) with
three OH groups was shown to exhibit an increase in the
fluorescence quantum yield as a result of intramoleclar hydro-
gen bond formation.
4
00
500
wavelength / nm
Figure 9. Fluorescence spectra of naphthalimides 1 and 2a
0.075 mM) in the presence of styrene at various concen-
(
On the contrary, our results clearly indicate that the
introduction of only one hydroxy group into the N-alkyl side
trations in dichloromethane.
nπ*
S2
nπ*
nπ*
τf = 180 ps
∆E
Tn
S2
S1
kisc = 5.1
kisc = 2.3
9
-1
nπ*
ππ*
9
-1
× 10 s
τf = 371 ps
× 10 s
∆E
Tn
T1
S1
ππ*
ππ*
T1
ππ*
h
ν
hν
kq = 1.62
kq = 1.45
Φf = 0.030
Φf = 0.060
1010 M s
-1 -1
10
-1 -1
×
Ph
× 10 M s
Ph
S0
S0
O
H
Me
N
O
O
O
N
2
O
a
1
Scheme 2.

1
072 Bull. Chem. Soc. Jpn. Vol. 83, No. 9 (2010)
Photophysical Properties of Naphthalimides
diameter). The intensity change of the probe beam was detected
by a photomultiplier. The TRTL signals were recorded on a
digitizing oscilloscope and were averaged over five hundred
laser shots to improve the signal-to-noise ratio. The absorbance
of the sample solutions for the TRTL measurements was
adjusted to ca. 0.10 at the excitation wavelength. The TRTL
experiments were carried out at 293 K.
C(CH OH)3
2
O
N
O
The equilibrium geometries of 2a and 3a were optimized
by DFT calculations by using the B3LYP functional and
2
2
4
6
6
-31+G(d) basis set. Total energies were evaluated by using
-311+G(d,p) basis set, and corrected with zero point vibration
Chart 1. Structural formula of 4.
energies. All theoretical calculations were carried out on
2
3
chain increases the fluorescence quantum yield of 1,8-naph-
thalimides about two times. The ability to markedly control the
photophysical properties and photoreactivities of 1,8-naph-
thalimide derivatives with the simple introduction of a single
intramolecular hydrogen bond may be of significant interest
given that naphthalimides are widely used in numerous
applications.
Gaussian 03 package.
Materials. N-Methyl-1,8-naphthalimide (1) was prepared
2
7
according to the published procedure. Solvents and styrene
were commercially available.
N-(2-Hydroxyethyl)-1,8-naphthalimide (2a):
thalimide 2a was prepared from 2-aminoethanol (15 mL,
250 mmol) and 1,8-naphthalic anhydride (20 g, 100 mmol)
according to the procedure reported for 1. Recrystallization of
the crude material from methanol gave 24 g (99 mmol) of 2a in
Naph-
Experimental
1
General. UV spectra were measured by use of a JASCO
UVIDEC-650 spectrometer. Fluorescence spectra were ob-
tained on a Hitachi 850 spectrophotometer. Melting points were
obtained on a Yanagimoto micro melting point apparatus and
are uncorrected. NMR spectra were recorded on a JEOL JNM-
AL-400 (400 MHz) instrument. Chemical shifts are reported in
99% yield as colorless columns. Mp 177.0­178.0 °C. H NMR
(CDCl3): ¤ 2.38 (t, J = 5.6 Hz, 1H), 3.99 (dt, J = 5.4, 5.6 Hz,
2H), 4.47 (t, J = 5.4 Hz, 2H), 7.77 (dd, J = 7.3, 8.3 Hz, 2H),
8.23 (d, J = 8.3 Hz, 2H), 8.61 (d, J = 7.3 Hz, 2H). 1 C NMR
(CDCl ): ¤ 42.8 (CH ), 61.9 (CH ), 122.4 (C), 127.0 (CH),
3
3
2
2
128.2 (C), 131.5 (CH), 131.6 (C), 134.2 (CH), 165.1 (C=O).
ppm (¤) relative to an internal standard (SiMe ). IR spectra
IR (KBr): 3484, 1698, 1655, 1588, 1380, 1348, 1323, 1235,
4
¹
1
+
were obtained using a JASCO FT/IR-350 spectrometer. Mass
spectra (EI, 70 eV) were recorded on a Hitachi M-80B mass
spectrometer. Combustion analyses were performed on a
Yanagimoto CHN corder MT-5.
1032, 778 cm . MS (70 eV): m/z 241 (M , 10), 222 (12), 210
(68), 198 (100), 180 (72), 152 (61), 126 (83). Found: C, 70.02;
H, 4.80; N, 5.95%. Calcd for C14H11NO3: C, 69.70; H, 4.60; N,
5.81%.
The picosecond lifetime measurements were carried out by
using a self-mode-locked Ti:sapphire laser (center wavelength
N-(2-Methoxyethyl)-1,8-naphthalimide (2b): To a meth-
anol solution (100 mL) of 2a (6.8 g, 28 mmol) was added
sulfuric acid (8.0 mL), followed by refluxing for 8 h. The
solution was then poured into 300 mL of water and the
precipitate filtered. Recrystallization of the crude material from
methanol gave 0.43 g (1.7 mmol) of 2b in 6% yield as colorless
8
00 nm, pulse width ca. 70 fs, repetition rate 82 MHz) pumped
3
+
by a Nd :YAG laser (532 nm, 4.5 W). The generation of
the second harmonic (400 nm, pulse width ca. 200 fs) was
performed in a lithium triborate (LBO) crystal. The third
harmonic (266 nm, pulse width ca. 250 fs) was generated by a
sum frequency mixing of the fundamental and the second
harmonic. The repetition frequency of the excitation pulse was
reduced to 4 MHz by using a pulse picker. The second
harmonic (400 nm) in the output beam was used as trigger
pulse. The fluorescence from the sample solution was observed
through a polarizer at the magic angle (54.7°) with respect to
the polarization direction of the excitation laser pulse. The
emission light was detected by a microchannel plate after
passing through a monochromator. The instrument response
function had a half-width of 20­25 ps. Analysis of the
fluorescence decay curves was carried out using the deconvo-
lution method.
1
columns. Mp 124.0­125.0 °C. H NMR (CDCl3): ¤ 3.39 (s,
3H), 3.74 (t, J = 5.9 Hz, 2H), 4.46 (t, J = 5.9 Hz, 2H), 7.75
(dd, J = 7.3, 8.5 Hz, 2H), 8.22 (d, J = 8.5 Hz, 2H), 8.62 (d,
1
3
J = 7.3 Hz, 2H). C NMR (CDCl ): ¤ 39.0 (CH ), 58.6 (CH ),
3
2
3
69.5 (CH ), 122.3 (C), 126.6 (CH), 127.8 (C), 131.0 (CH),
2
131.3 (C), 133.6 (CH), 163.9 (C=O). IR (KBr): 1698, 1658,
¹
1
1591, 1438, 1376, 1359, 1235, 1120, 1046, 783 cm . MS
+
(70 eV): m/z 255 (M , 85), 223 (80), 210 (89), 197 (42), 180
(89), 152 (92), 126 (100). Found: C, 70.71; H, 5.30; N, 5.59%.
Calcd for C H NO : C, 70.58; H, 5.13; N, 5.49%.
1
5
13
3
N-(3-Hydroxypropyl)-1,8-naphthalimide (3a):
Naph-
thalimide 3a was prepared from n-propanolamine (45 mL,
590 mmol) and 1,8-naphthalic anhydride (60 g, 300 mmol).
Recrystallization of the crude material from methanol gave 54 g
The quantum yields for intersystem crossing (Φ ) in
isc
naphthalimides were determined by means of the time-resolved
thermal lensing (TRTL) method. For TRTL measurements, the
third harmonic (355 nm) of a nanosecond Nd3 :YAG laser
(300 mmol) of 3a in a quantitative yield as colorless needles.
1
Mp 123.0­124.0 °C. H NMR (CDCl ): ¤ 2.00 (m, 2H), 3.15
3
+
(t, J = 6.9 Hz, 1H), 3.59 (dt, J = 6.1, 6.9 Hz, 2H), 4.36 (t,
J = 6.1 Hz, 2H), 7.78 (dd, J = 7.3, 8.3 Hz, 2H), 8.24 (d,
(pulse width 6 ns) was utilized for the excitation source. A
1
3
He-Ne laser beam (633 nm) was used as the monitoring light.
The probe light was introduced into a monochromator after
passing through an optical filter and a small pinhole (300 ¯m
J = 8.3 Hz, 2H), 8.63 (d, J = 7.3 Hz, 2H). C NMR (CDCl ): ¤
3
30.9 (CH ), 36.7 (CH ), 58.8 (CH ), 122.2 (C), 126.9 (CH),
2
2
2
128.1 (C), 131.5 (C), 131.5 (CH), 134.2 (CH), 164.7 (C=O).

K. Matsubayashi et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 9 (2010) 1073
C. A. G. O. Varma, Chem. Phys. 1995, 201, 525.
11 a) A. Sinicropi, W. M. Nau, M. Olivucci, Photochem.
Photobiol. Sci. 2002, 1, 537. b) J. Waluk, Acc. Chem. Res. 2003,
IR (KBr): 3435, 1695, 1644, 1620, 1591, 1346, 1245, 1173,
¹1
+
9
(
23, 785 cm . MS (70 eV): m/z 255 (M , 72), 222 (72), 211
92), 197 (45), 180 (84), 152 (86), 126 (100). Found: C, 70.77;
H, 5.25; N, 5.61%. Calcd for C H NO : C, 70.58; H, 5.13; N,
3
6, 832.
V. Wintgens, P. Valat, J. Kossanyi, L. Biczok, A. Demeter,
T. Bérces, J. Chem. Soc., Faraday Trans. 1994, 90, 411.
15
13
3
1
2
5
.49%.
N-(3-Methoxypropyl)-1,8-naphthalimide (3b):
To a
13
14
15
16
E. Martin, R. Weigand, A. Pardo, J. Lumin. 1996, 68, 157.
I. Grabtchev, T. Philipova, Dyes Pigm. 1995, 27, 321.
W. Yao, X. Qian, Q. Hu, Tetrahedron Lett. 2000, 41, 7711.
M. F. Braña, J. M. Castellano, M. Morán, M. J. Pérez de
methanol solution (300 mL) of 3a (8.0 g, 31 mmol) was added
sulfuric acid (20 mL), followed by refluxing for 24 h. The
solution was then poured into 300 mL of water and the
precipitate filtered. Recrystallization of the crude material from
methanol gave 3.7 g (14 mmol) of 3b in 44% yield as colorless
cubics. Mp 100.0­101.0 °C. H NMR (CDCl ): ¤ 2.03 (m, 2H),
Vega, X. D. Qian, C. A. Romerdahl, G. Keilhauer, Eur. J. Med.
Chem. 1995, 30, 235.
1
3
1
7
P. F. Bousquet, M. F. Braña, D. Conlon, K. M. Fitzgerald,
3
.34 (s, 3H), 3.53 (t, J = 6.6 Hz, 2H), 4.29 (t, J = 6.6 Hz, 2H),
.75 (dd, J = 7.1, 8.5 Hz, 2H), 8.21 (d, J = 8.5 Hz, 2H), 8.61
D. Perron, C. Cocchiaro, R. Miller, M. Moran, J. George, X. D.
Qian, G. Keilhauer, C. A. Romerdahl, Cancer Res. 1995, 55, 1176.
7
(
d, J = 7.1 Hz, 2H). 13C NMR (CDCl3): ¤ 28.1 (CH2), 37.7
1
8
L. M. Daffy, A. P. de Silva, H. Q. N. Gunaratne, C. Huber,
(
CH ), 58.4 (CH ), 70.5 (CH ), 122.5 (C), 126.7 (CH), 127.9
2
3
2
P. L. M. Lynch, T. Werner, O. Wolfbeis, Chem.®Eur. J. 1998, 4,
(C), 130.9 (CH), 131.4 (C), 133.6 (CH), 163.8 (C=O). IR
1810.
(
KBr): 1696, 1657, 1626, 1589, 1443, 1344, 1233, 1116, 906,
19 B. Ramachandram, G. Saroja, N. B. Sankaran, A. Samanta,
J. Phys. Chem. B 2000, 104, 11824.
20 Y. Kubo, M. Suto, S. Tojo, T. Araki, J. Chem. Soc., Perkin
Trans. 1 1986, 771.
¹
1
+
7
1
5
5
83 cm . MS (70 eV): m/z 269 (M , 41), 222 (42), 211 (79),
98 (100), 180 (65), 152 (64), 126 (65). Found: C, 71.42; H,
.78; N, 5.33%. Calcd for C H NO : C, 71.36; H, 5.61; N,
16
15
3
.20%.
21 K. Matsubayashi, Y. Kubo, J. Org. Chem. 2008, 73, 4915.
2
2
a) A. D. Becke, J. Chem. Phys. 1993, 98, 5648. b) C. Lee,
Supporting Information
W. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785. c) P. J. Stephens,
F. J. Devlin, C. F. Chabalowski, M. J. Frisch, J. Phys. Chem. 1994,
Parameters of the coordinates of optimized geometries of 2a
and 3a. This material is available free of charge on the web at:
http://www.csj.jp/journals/bcsj/.
9
8, 11623.
M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,
2
3
M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B.
Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P.
Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg,
M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida,
T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J. A.
Montgomery, Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd,
E. Brothers, K. N. Kudin, V. N. Staroverov, R. Kobayashi, J.
Normand, K. Raghavachari, A. Rendell, J. C. Burant, S. S.
Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klene,
J. E. Knox, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R.
Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C.
Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma, V. G.
Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S.
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